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Viewing 1 to 30 of 10300
2015-09-15
Technical Paper
2015-01-2521
Manimaran Govindarasu, Aditya Ashok
Many critical infrastructures, such as energy and transportation systems, are cyber-enabled physical systems that increasingly rely on smart sensors, communication networks, and control algorithms for their efficient, reliable, and economic operations. Risk modeling is a key component of any comprehensive security solution to protect these infrastructures against cyber attacks. In this paper, we present a quantitative methodology for risk assessment and mitigation for cyber-physical systems and contrast its strengths and weaknesses with respect to qualitative risk assessment methodology that is widely used in industry.
2015-09-15
Technical Paper
2015-01-2520
Thabet Kacem, Jeronymo Carvalho, Duminda Wijesekera, Paulo Costa, Márcio Monteiro, Alexandre Barreto
Since its emergence, Automatic Dependent Surveillance Broadcast (ADS-B) has been considered as a major contribution to air traffic control (ATC) surveillance. However, despite the several benefits that this promising technology has to offer, it suffers from a major security flaw since ADS-B packets are sent in clear text without enforcing any kind of security property. In this paper, we enhance a security framework, which we describe in a previous paper, aiming at detecting and mitigating attacks targeting ADS-B protocol, with a cognitive engine. First, this would facilitate the physical risk assessment of the ADS-B attacks based on the collected data describing the aircraft and its surrounding. Second, it would be beneficial to the ATC controllers who would have a better idea about the best ways to optimize the aircraft taking off and touching down without any disruptions from possible attacks targeting this technology.
2015-09-15
Technical Paper
2015-01-2519
Rosa Maria Rodriguez, Javier Garcia, Pedro Taboso
Boeing Research & Technology Europe (BR&T-Europe), a subsidiary of The Boeing Company, is developing an innovative approach to Communication, Navigation and Surveillance (CNS) in order to enhance both security and efficiency. Our approach will use the broadband internet connection onboard to securely interchange CNS data between aircraft and ground. On board broadband will allow new technological solutions and applications, not possible with current approaches, in a more secure and cost effective way. It also supports permanent surveillance and virtual event data recorder (black box). This concept is based on the dramatic improvement of broadband services on board. With some internet service providers promising up to 50Mbps per aircraft and global coverage, traditional data links (ACARS and ATN) are becoming obsolete. The solution supports the concept of aircraft always connected to ground servers to delocalize and automatize some CNS features.
2015-09-15
Technical Paper
2015-01-2538
Yixiang Lim, Alessandro Gardi, Roberto Sabatini
With the currently foreseen growth of air traffic globally, the effects of aircraft condensation trails (contrails) are predicted to become significant by 2050. Currently, the physics behind the formation of contrails is relatively well understood. However, research regarding the persistence or dissipation timescales of contrails is still ongoing, with particular focus on their evolution into cirrus clouds, since these clouds have been shown to contribute to global warming. Currently, the formation of cirrus is believed to be affected by the microphysics of contrail formation and possibly by wind shear. In the aviation industry, there is an ongoing progress in the development of an integrated flight management/air traffic management system to account for contrail mitigation.
2015-09-15
Technical Paper
2015-01-2539
Alessandro Gardi, Roberto Sabatini, Subramanian Ramasamy, Matthew Marino, Trevor Kistan
The potential benefits offered by advanced aircraft navigation technologies will be ultimately exploited only through the dynamic allocation of resources in a highly automated airspace. In this respect, the deployment of Four Dimensional Trajectory (4DT) functionalities in an Intent Based Operations (IBO) environment is envisaged as a fundamental enabler of future Air Traffic Management (ATM) services. The 4DT-IBO, in turn, are requiring the introduction of novel Communications, Navigation and Surveillance and ATM (CNS/ATM) systems, enabling the migration from traditional voice communications to data-driven negotiation and validation functions. A novel ground-based 4DT Planning, Negotiation and Validation (4-PNV) system is being developed in conjunction with Next Generation Flight Management Systems (NG-FMS) and Mission Management Systems (NG-MMS) for integration into the future air traffic scenario.
2015-09-15
Technical Paper
2015-01-2540
Haochang Deng
Event of the disappearance of MH370 for a prolonged period of time makes the International Civil Aviation Organization (ICAO) to have reiterated the need to improve global flight tracking capabilities in the near term. Civil Aviation Administration of China (CAAC) has put forward a road map for using of 1090ES ADS-B to track flight en route. This paper provides the airborne systems solution. The systems are based on Integrated Modular Avionics (IMA) architecture, adding 1090ES function on Mode-S transponder and TCAS for ADS-B out function and ADS-B in function, and also using SATCOM system data link to receive and transmit data, such as aircraft position, height, velocity, flight ID, aircraft intents, etc. After ADS-B transmitted data is received by ground data communication center, it can be distributed to air traffic management bureaus and airlines control cementer, for tracking the flight.
2015-09-15
Technical Paper
2015-01-2556
Thomas Rousselin, Guillaume Hubert, Didier Regis, Marc Gatti
The changes brought by the increasing integration density and the new technological trends have pushed the reliability at its limit. Safety analysis for critical system such as embedded electronics for avionics systems needs to take into account these changes. In this paper, we present the consequences on the Deep Sub-Micron (DSM) CMOS devices concerning their single event effect (SEE) sensitivity. We also propose a new modeling method in order to address these issues.
2015-09-15
Technical Paper
2015-01-2429
Rickard Olsen, Kerstin Johansen, Magnus Engstrom
The diffusion of human and robotics in manufacturing system is one of the next steps in robotics. Since the computer power gets more and more powerful there is more and more possible to achieve safer working environment. This could lead to a possibility to work closer and more direct with a robot. In an EU FW7 funded project called LOCOMACHs (Low Cost Manufacturing and Assembly of Composite and Hybrid Structures) there are studies and tests to support a future higher TRL-leveled HMI-cell (Human Machine Interaction). The main object in this paper is to present how different safety system could help the HMI-cell to work properly in an industrial context, this when the operator enters the robot working area and working with a task that needs two hand. Safety defines as when its risk is judged to be acceptable.
2015-09-15
Technical Paper
2015-01-2433
Simon Taylor
Within the aerospace domain advisory material and recommended practices exist to support the structured safety assessment in response to certification requirements; specifically 25.1309 for large transport category aircraft. This material provides structured guidance for safety assessment including Common Cause Analysis (CCA) however the approaches are largely dependent upon the experience and competence of the practitioner. In the context of fewer and shorter product development programs, lengthening operational lifetimes, increasing system integration and development complexity, as well as the trend for delegated responsibility to system suppliers there is a need for a more structured approach which supported the preservation of knowledge. This paper summarizes the current state of the art within the aerospace domain from the perspective of CCA and proposes a knowledge centric approach as part of a front loaded development process.
2015-09-15
Technical Paper
2015-01-2432
Michael Hanna
One of the most important system development issues facing developing new aerospace systems is how to comply with the complex design requirements and in the same time ensure compliance to the associated safety requirements. There is an increased need to develop complex and critical aerospace systems that depend on high integration between the Hardware and the Software to achieve efficiency and optimization. This level of complexity imposes significant challenge in complying and achieving the required level of safety. This paper addresses the safety challenges that are imposed by developing complex systems to fulfill critical functions with the focus on the common cause errors and the compliance to the Design Assurance Level. The design doesn’t only need to take in consideration assigning proper Design Assurance Level for each function, but also providing immune against common cause errors.
2015-09-15
Technical Paper
2015-01-2431
Robert E. Voros
Aerospace Recommended Practice 4754 Revision A (ARP4754A), “Guidelines for Development of Civil Aircraft and Systems,” is recognized through Advisory Circular 20-174 (AC 20-174) as a way (but not the only way) to provide development assurance for aircraft and systems to minimize the possibility of development errors. ARP4754A and its companion, Aerospace Information Report (AIR) 6110, “Contiguous Aircraft/System Development Process Example,” primarily describe development processes for an all new, complex and highly integrated aircraft without strong consideration for reused systems or simple systems. While ARP4754A section 5 mention reuse, similarity, and complexity, and section 6 is intended to cover modification programs, the descriptions in these sections can be unclear and inconsistent. The majority of aircraft projects are normally not completely new products nor are they entirely comprised of complex and highly-integrated systems.
2015-09-15
Technical Paper
2015-01-2437
Simon Taylor
Interconnection systems are passive systems which merely afford the transfer of data and/or power between the items of an active system, thereby supporting the system function. The safety assessment of these interconnection systems may be considered to be fundamentally similar across the different power and data transfer technologies; whether electromagnetic or mechanical interconnection systems. Within the aerospace domain advisory material and recommended practices exist to support safety assessment in response to certification requirements; specifically for large transport category aircraft 25.1309 and 25.1709. This material provides an outline process for interconnection system safety assessment in terms of physical and functional failures.
2015-09-15
Technical Paper
2015-01-2436
Anapathur V. Ramesh
Fault-tolerance in commercial aircraft applications is typically achieved by redundancy. Dual or triple redundancy is common, and higher redundancy aircraft systems exist. This is also true for the Military, Defense and Space vehicles. In many cases the backups are provided for safety, and are used only to provide functionality when the primary fails. In such systems the primary component is checked before the start of a flight to see if it operates correctly. The aircraft will not take off unless the primary is functioning. Usually backup components are checked at intervals that span multiple flights. The first backup may be checked more frequently than the second or higher levels. This leads to flights where the system could have latent faults in the backup components. The probability of failure in such cases varies from flight to flight due to the different exposure times for components in the system.
2015-09-15
Technical Paper
2015-01-2435
Ramakrishnan Murthy
One major problem that any product (say Motor, engines etc) which converts electrical energy into a mechanical energy would have is resonance. It has tendency to damage any material when the products operating frequency matches the resonant frequency. The major consequences of this resonant frequency in Flight at run-time could be catostrophic. Generally it is a practice to avoid running at the resonant frequency. This is done as a fixed method where the systems are designed not to run on resonant frequency, i.e. a subsystem in a system is now being designed for that system alone which will not match the resonant frequency. But the same subsystem may not be suitable for some other system. Hence this requires multiple designs. However this idea is to make a design generic where any subsystem can be used in any system irrespective of its resonant frequency. The technique uses the PID algorithm. This method will be helpful is having a single design for different systems.
2015-09-15
Technical Paper
2015-01-2434
Tian Lirong, Mu Ming
Abstract: Chinese aviation industry is now making great efforts in developing civil aircraft, as a result, more opportunities for Chinese companies to be involved in these programs, but Chinese companies are lack of experience in this area, certification is one of the challenges for them,so they are expected to be more competitive in design and certification. ACTRI (Aeronautical Computing Technique Research Institute) is a airborne computer supplier in China, to be able to develop electronic equipment for civil aircraft, the company has being working on processes improvement including the system process based on ARP4754 since 2008. This paper describes the customized system process in Chinese context.
2015-09-15
Technical Paper
2015-01-2442
Srikanth Gururajan, Jennifer Gritton
With the release of a draft set of rules by the FAA allowing the flights of Unmanned Aerial Systems (UAS) in the National Airspace System (NAS), with certain restrictions on their operations, it is inevitable that in the near future UAS operations will extend beyond line of sight to fully autonomous or intermittently autonomous operations over long distances. Such operations would involve extensive interaction between the UAS and manned aircraft under various flight conditions and consequently, issues of operational safety arise on both sides – manned and unmanned. In this effort, we explore the development of cooperative operational protocols for various phases of flight to ensure safe interaction in the NAS, building upon the well-established FAA operational protocols in manned aviation, as well as the wealth of experience from remote control model aircraft flight operations.
2015-09-15
Technical Paper
2015-01-2438
Robert E. Voros
Aerospace Recommended Practice 4754 Revision A (ARP4754A), “Guidelines for Development of Civil Aircraft and Systems,” and ARP4761, “Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment,” together describe a complex set of intertwining processes which comprehensively prioritize development activities for a product’s systems based on their safety criticality. These processes work at specific levels of detail (aircraft and system) and interact with a set of processes at lower levels of detail (item) defined by Radio Technical Commission for Aeronautics (RTCA) standards. The aircraft and system development process (ARP4754A) supplies functions, requirements, and architectural definitions to the system safety process (ARP4761), which in turn supplies Development Assurance Levels back to the development process and on to the RTCA processes.
2015-09-15
Technical Paper
2015-01-2440
Robert Moehle, Jason Clauss
From the dawn of commercial air travel until 2001, labor costs loomed as the greatest expense in commercial aviation. Though fuel costs have since taken the top spot, labor costs remain a pressing area of concern in the airline industry. Airlines have long sought to reduce the burden of labor to improve the businesses’ bottom line. One of their most frequent appeals has been to allow a single flight crew member to operate the aircraft. Safety concerns represent the dominant barrier to single-pilot Part 121 operations. The FAA and Congress consistently demonstrate a bias toward conservatism in their regulation of airlines and commercial aircraft. Under-educated on the true failure rates, bureaucrats and the general public fall prey to isolated news stories about pilots becoming ill or falling asleep in the flight deck. Yet, in an alarming spate of recent airline accidents, the presence of multiple crewmembers did nothing to prevent, and actually may have contributed to, the crash.
2015-09-15
Technical Paper
2015-01-2441
Ahmet Oztekin
Air Traffic Control System (ATCS) provides organizational, operational, and technical infrastructure necessary to maintain air traffic separation and prevent collision between aircraft operating within civil airspace. Current aviation safety research focuses mainly on aircraft and human vs. machine interactions. There is a gap in literature regarding research that explores ATCS’s potential impact on aviation safety. For complex systems, such as ATCS, safety is primarily a product of potential interactions among its various sub-systems. For example, over the phases of flight, separation of air traffic is maintained by different types of air traffic control (ATC) facilities. This paper outlines an analytical framework to perform a data-driven, risk-based assessment of ATC facilities. Safety associated with an ATC facility is modeled as an influence network using a set of risk factors.
2015-09-15
Technical Paper
2015-01-2456
Roberto Sabatini, Terry Moore, Chris Hill
The integration of Global Navigation Satellite System (GNSS) integrity augmentation functionalities in Unmanned Aerial Vehicles (UAV) Detect-and-Avoid (DAA) architectures has the potential to provide an integrity-augmented DAA solution suitable for cooperative and non-cooperative scenarios. In this paper, we evaluate the opportunities offered by this integration, proposing a novel approach that maximizes the synergies between Avionics Based Integrity Augmentation (ABIA) and UAV cooperative/non-cooperative DAA architectures. In the proposed architecture, the risk of collision is evaluated by setting a threshold on the Probability Density Function (PDF) of a Near Mid-Air Collision (NMAC) event over the separation area in both cooperative and non-cooperative cases.
2015-09-15
Technical Paper
2015-01-2469
Reece Clothier, Brendan Williams, Achim Washington
One on the primary hazards associated with the operation of Unmanned Aircraft (UA) is the controlled or uncontrolled impact of the UA with terrain or objects on the terrain (e.g., people or structures). National Aviation Authorities (NAAs) have the responsibility of ensuring that the risks associated with this hazard are managed to an acceptable level. The NAA can mandate a range of technical (e.g., design standards) and operational (e.g., restrictions on flight) regulatory requirements. However, work to develop these regulations for UA is ongoing. Underpinning this rule-making process is a safety case showing how the regulatory requirements put in place ensure that the UA operation is acceptably safe for the given application and environment.
2015-09-15
Technical Paper
2015-01-2470
Subramanian Ramasamy, Roberto Sabatini, Alessandro Gardi
Cooperative and non-cooperative Detect-and-Avoid (DAA) functions are key enablers for Remotely Piloted Aircraft System (RPAS) to safely and routinely access all classes of airspace. In this paper state-of-the-art cooperative and non-cooperative DAA sensor/system technologies for manned aircraft and RPAS are reviewed and the associated multi-sensor data fusion techniques are discussed. A DAA system architecture is presented based on Boolean Decision Logics (BDL) for selecting non-cooperative and cooperative sensors/systems including both passive and active Forward Looking Sensors (FLS), Traffic Collision Avoidance System (TCAS) and Automatic Dependent Surveillance – Broadcast (ADS-B). After elaborating the DAA system processes, the key mathematical models associated with both non-cooperative and cooperative DAA functions are presented.
2015-09-15
Technical Paper
2015-01-2430
Locking of threaded members is to date accomplished by a variety of engineering solutions. Generally speaking, in terms of separate locking devices or by built-in locking features such as friction generating means. The Autonomous and instant Acting Thread Locking Mechanism (ATLM) has been developed by IBW for combining the merits of safe joining, fast installation process, and no prevailing torque generated by the locking means. The ATLM uses a freewheel (clutch) which is securely installed in either one of the two threaded members and releaseably coupled with the engaged counterpart. While screwing the threaded members together, once coupled, the freewheel will allow free mating of the threaded members including torqueing to the desired value. The moment, the pair of threaded fasteners is forced to unscrew (by intended or unintended occurrence of torque in the undoing direction) the freewheel does lock instantly.
2015-06-15
Technical Paper
2015-01-2112
Thomas Schlegl, Michael Moser, Hubert Zangl
Abstract We present a wireless sensor system for temperature measurement and icing detection for the use on aircraft. The sensors are flexible (i.e. bendable), truly wireless, do not require scheduled maintenance, and can be attached easily to almost any point on the aircraft surface (e.g. wings, fuselage, rudder, elevator, etc.). With a sensor thickness of less than two millimeters at the current state of development, they hardly affect the aero dynamical behavior of the structure. In this paper, we report laboratory and field results for temperature measurement and icing detection.
2015-06-15
Technical Paper
2015-01-2082
Andreas Tramposch, Wolfgang Hassler, Reinhard F.A. Puffing
Abstract Certain operating modes of the Environmental Control System (ECS) of passenger aircraft are accompanied with significant ice particle accretion in a number of pivotal parts of the system. Icing conditions particularly prevail downstream of the air conditioning packs and, as a consequence, ice particle accretion takes place in the Pack Discharge Duct (PDD) and in the mixing manifold. For a better understanding of these icing processes, numerical simulations using a multiphase model based on a coupled Eulerian-Lagrangian transport model in a generic PDD were performed. The obstruction of the PDD due to ice growth and the resulting change of the flow geometry were treated by deforming the computational mesh during the CFD simulations. In addition to the numerical investigations, a generic and transparent PDD was studied experimentally under several operating conditions in FH JOANNEUM's icing wind tunnel.
2015-06-15
Technical Paper
2015-01-2081
Hossein Habibi, Graham Edwards, Liang Cheng, Haitao Zheng, Adam Marks, Vassilios Kappatos, Cem Selcuk, Tat-Hean Gan
Abstract Icing conditions in cold regions of the world may cause problems for wind turbine operations, since accreted ice can reduce the efficiency of power generation and create concerns regarding ice-shedding. This paper covers modelling studies and some experimental development for an ongoing ice protection system that provides both deicing and anti-icing actions for wind turbine blades. The modelling process contained two main sections. The first part involved simulation of vibrations with very short wavelength or ultrasonic guided waves (UGW) on the blade to determine optimal excitation frequency and transducer configuration. This excitation creates horizontal shear stress at the interface between ice and blade and focuses energy at the leading edge for de-bonding ice layers.
2015-06-15
Technical Paper
2015-01-2080
Roger J. Aubert
Abstract The entire process from ice accretion to ice impact with ice shedding in between still needs refinement. This paper presents key points illustrating the need for improvements in understanding the mechanical properties of ice accretion on helicopter rotor systems.
2015-06-15
Technical Paper
2015-01-2079
Colin Hatch, Jason Moller, Eleftherios Kalochristianakis, Ian Roberts
Abstract The introduction of ice-phobic coatings promises to allow passive ice protection systems to be developed particularly for rotating systems such as propellers. The centrifugal force field combined with reduced adhesive strength can produce a self-shed capability limiting the amount of ice build-up. The size and shed time of ice shed from a propeller is predicted using a process that determines ice shape, ice growth rate and both internal and ice-structure interface stresses. A simple failure model is used to predict the onset of local failure and to propagate damage in the ice until local ice shedding is obtained. Recommendations are made on developing the model further.
2015-06-15
Technical Paper
2015-01-2078
Alric Rothmayer, Hui Hu
Abstract A strong air/water interaction theory is used to develop a fast simplified model for the trapping of water in a film that flows over sub-grid surface roughness. The sub-grid model is used to compute correction factors that can alter mass transport within the film. The sub-grid model is integrated into a covariant film mass transport model of film flow past three-dimensional surfaces in a form that is suitable for use in aircraft icing codes. Sample calculations are presented to illustrate the application of the model.
2015-06-15
Technical Paper
2015-01-2076
Caroline Laforte, Neal Wesley, Marc Mario Tremblay
Abstract This study presents a new method to evaluate and compare the anti-icing performance, i.e., the ability to delay the reformation of ice, of runways and taxiways deicing/anti-icing fluids (RDF) under icing precipitation, based on the skid resistance values, obtained with the Portable Skid Resistance Tester (PSRT). In summary, the test consists of applying, on a standardized concrete pavement sample, a given quantity of de-icing fluid. Following this application, the concrete sample is submitted to low freezing drizzle intensities, in a cold chamber at −5.0 ± 0.3°C. The skid resistance of concrete is measured at 5 minute intervals, until the concrete becomes completely iced. The anti-icing performance of 5 different fluids, both experimental and commercial, was assessed in comparison with a reference solution of 50% w/w K-formate. The anti-icing performance is analyzed based on two parameters: the duration (Icing Protection Time, IPT) and the effectiveness of this protection.
Viewing 1 to 30 of 10300